Encapsulating active components in edible compositions to prolong their release and/or to slow their degradation is known. Encapsulating materials used to coat such components include, for example, cellulose, cellulose derivatives, arabinogalactin, gum arabic, polyolefins, waxes, vinyl polymers, gelatin, zein and mixtures thereof. The encapsulating materials have been used to protect active components such as sweeteners, acids, flavorings, soluble dietary fibers, biologically active agents such as pharmaceutical compounds or medicinal drugs, breath freshening agents, and the like.
Attempts have been made to encapsulate active components such as sweeteners, particularly high intensity sweeteners to prevent against premature degradation, to enhance the uniformity of release, and to prolong release in a controlled manner. High intensity sweeteners generally have a sweetening intensity greater than sugar (sucrose) and a caloric value lower than that of sugar at equivalent sweetness levels. It is especially desirable to control the release of high intensity sweeteners in compositions since the high sweetness levels can easily overwhelm the consumer. Moreover, the controlled release of the sweetener provides desirable masking of unpleasant tasting materials. Because each high intensity sweetener is chemically and physically distinct, each is a challenge to use in an edible composition and each exhibits one or more shortcomings, which may be moderated by encapsulation.
For example, many high intensity sweeteners lose their sweetness intensity rapidly when used in edible compositions such as chewing gums and confections. Encapsulation can modulate and prolong release to provide a more desirable taste profile. Some high intensity sweeteners such as saccharin, stevioside, acesulfame-K, glycyrrhizin, and thaumatin have an associated bitter taste or off-note. Certain high intensity sweeteners are also unstable in the presence of certain chemicals including aldehydes and ketones, and sensitive to exposure to environmental conditions including moisture. Solid sucralose is known to turn dark during prolong storage upon exposure to heat and ambient air. Encapsulation can be used to isolate unstable compounds to prevent degradation and prolong shelf life.
Typically, the taste profile of a high intensity sweetener can be described as a rapid burst of sweetness. Usually, high intensity sweeteners reach their peak sweet taste rapidly, with the intensity of sweet taste rapidly declining soon thereafter. The initial rapid burst can be unpleasant to many consumers as the strong sweet taste tends to overpower the other flavors that may be present in the edible composition. The relatively rapid loss of sweetness can also result in a bitter aftertaste. For this reason, it is typically desirable to encapsulate high intensity sweeteners with an encapsulating material in order to modulate and prolong the release rate and to chemically stabilize and enhance the overall taste profile. The selection of a suitable encapsulating material (i.e., polyvinyl acetate) has usually been focused on the molecular weight of the encapsulating material with higher molecular weights generally associated with longer release times.
By way of example, U.S. Pat. No. 4,711,784 to Yang discloses a chewing gum composition containing a high molecular weight polyvinyl acetate blended with a hydrophobic plasticizer as an encapsulating material. The encapsulating material is used to encapsulate an active ingredient such as aspartame.
U.S. Pat. No. 4,816,265 to Cherukuri et al. discloses a sweetener delivery system, which uses a coating composed of an emulsifier and a polyvinyl acetate encapsulating material having a molecular weight of from about 2,000 to 14,000, optionally in the presence of a wax. The coating is applied to sweeteners such as aspartame to effectuate sustained release of the sweetener.
U.S. Pat. No. 5,057,328 to Cherukuri et al. discloses a food acid delivery system for use in for example, chewing gums, having a food acid that is encapsulated in a matrix comprising an emulsifier and polyvinyl acetate in a specified molecular weight range.
U.S. Pat. No. 5,108,763 to Chau et al. discloses a sweetening agent delivery system having prolonged sweetener release. The system utilizes a high intensity sweetener encapsulated in polyvinyl acetate having a molecular weight in the range of from about 2,000 to 100,000. The system further includes the use of a plasticizing agent, a waxy material and an emulsifying agent.
U.S. Pat. No. 5,789,002 to Duggan et al. discloses a process for preparing sweeteners and acids as ingredients for chewing gum compositions. In particular, the Duggan et al. reference discloses encapsulating the sweetener or acid in a delivery system such as polyvinyl acetate.
U.S. patent application Ser. No. 2002/0122842 filed by Seiestad et al. discloses food mixtures including chewing gums containing at least two acids encapsulated by a polyvinyl acetate matrix. The polyvinyl acetate has a molecular weight in the range of from about 20,000 to 120,000.
The prior art systems identified above prepare encapsulating materials by taking into account the selection of an encapsulating material (e.g. polyvinyl acetate) and its molecular weight.
Since polyvinyl acetate is the most common encapsulating material, the molecular weight of the material becomes a critical feature in the making of prior art delivery systems. Thus, the state of the art for encapsulating active components especially high intensity sweeteners essentially associates controlled release of the active component with the molecular weight of the encapsulating material. However, this approach is limited in that the predictable modification of the controlled release of the active agent is made only through the modification of the molecular weight of the encapsulating material. There is no predictable modification based on the use of other encapsulating materials and/or additives that may be employed in the preparation of suitable delivery systems. Thus, there is no comprehensive approach to the production of a desirable delivery system that can provide a desirable release rate of an active component without engaging in a significant amount of trial and error experimentation.
It would therefore be a significant advance in the art to provide a process of producing delivery systems for the desirable release of an active component so that regardless of the type of the composition of the delivery system it will be suitable for the particular application (e.g., the controlled delivery of a high intensity sweetener).